In recent years, displays of image display devices including television receivers are shifting from conventional cathode-ray tube displays to thin-screen displays including liquid crystal panels and plasma display panels. With the thin-screen displays, thin image display devices can be provided. A liquid crystal display device requires a backlight unit as a separate lighting device because a liquid crystal panel used therein is not a light-emitting component. The backlight units are divided into two types including direct-type backlight units and side-light type backlight units depending on the mechanism. Patent Document 1 describes an example of the direct-type backlight units and Patent Document 2 describes an example of the side-light type backlight units.
Patent Document 1: Japanese Published Patent Application No. 2003-215350
Patent Document 1: Japanese Published Patent Application No. 2006-108045